diff --git a/app/Io/CheckinCsvImporter.php b/app/Io/CheckinCsvImporter.php
index 1fd2f0d..2a7bb91 100644
--- a/app/Io/CheckinCsvImporter.php
+++ b/app/Io/CheckinCsvImporter.php
@@ -4,18 +4,24 @@ namespace App\Io;
 
 use App\Ejaculation;
 use App\Exceptions\CsvImportException;
+use App\Rules\CsvDateTime;
 use App\Tag;
+use App\User;
 use Carbon\Carbon;
 use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Validator;
 use League\Csv\Reader;
 
 class CheckinCsvImporter
 {
+    /** @var User Target user */
+    private $user;
     /** @var string CSV filename */
     private $filename;
 
-    public function __construct(string $filename)
+    public function __construct(User $user, string $filename)
     {
+        $this->user = $user;
         $this->filename = $filename;
     }
 
@@ -45,48 +51,24 @@ class CheckinCsvImporter
             }
 
             foreach ($csv->getRecords() as $offset => $record) {
-                $ejaculation = new Ejaculation();
+                $ejaculation = new Ejaculation(['user_id' => $this->user->id]);
 
-                $checkinAt = $record['日時'] ?? null;
-                if (empty($checkinAt)) {
-                    $errors[] = "{$offset} 行 : 日時列は必須です。";
-                    continue;
-                }
-                if (preg_match('/\A20\d{2}[-/](1[0-2]|0?\d)[-/](0?\d|[1-2]\d|3[01]) (0?\d|1\d|2[0-4]):(0?\d|[1-5]\d)(:(0?\d|[1-5]\d))?\z/', $checkinAt) !== 1) {
-                    $errors[] = "{$offset} 行 : 日時列の書式が正しくありません。";
-                    continue;
-                }
-                $checkinAt = str_replace('/', '-', $checkinAt);
-                try {
-                    $ejaculation->ejaculated_date = Carbon::createFromFormat('!Y-m-d H:i+', $checkinAt);
-                } catch (\InvalidArgumentException $e) {
-                    $errors[] = "{$offset} 行 : 日時列に不正な値が入力されています。";
-                    continue;
-                }
+                $validator = Validator::make($record, [
+                    '日時' => ['required', new CsvDateTime()],
+                    'ノート' => 'nullable|string|max:500',
+                    'オカズリンク' => 'nullable|url|max:2000',
+                ]);
 
-                if (!empty($record['ノート'])) {
-                    $note = $record['ノート'];
-
-                    if (mb_strlen($note) > 500) {
-                        $errors[] = "{$offset} 行 : ノート列は500文字以内にしてください。";
-                        continue;
+                if ($validator->fails()) {
+                    foreach ($validator->errors()->all() as $message) {
+                        $errors[] = "{$offset} 行 : {$message}";
                     }
-
-                    $ejaculation->note = $note;
+                    continue;
                 }
 
-                if (!empty($record['オカズリンク'])) {
-                    $link = $record['オカズリンク'];
-
-                    if (mb_strlen($link) > 2000) {
-                        $errors[] = "{$offset} 行 : オカズリンク列は500文字以内にしてください。";
-                        continue;
-                    }
-
-                    // TODO: URL Validation
-
-                    $ejaculation->link = $link;
-                }
+                $ejaculation->ejaculated_date = Carbon::createFromFormat('!Y/m/d H:i+', $record['日時']);
+                $ejaculation->note = $record['ノート'] ?? '';
+                $ejaculation->link = $record['オカズリンク'] ?? '';
 
                 $tagIds = [];
                 for ($i = 1; $i <= 32; $i++) {
diff --git a/app/Rules/CsvDateTime.php b/app/Rules/CsvDateTime.php
new file mode 100644
index 0000000..118c5ba
--- /dev/null
+++ b/app/Rules/CsvDateTime.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace App\Rules;
+
+use Illuminate\Contracts\Validation\Rule;
+
+/**
+ * CSVインポート機能の日時バリデーションルール
+ * @package App\Rules
+ */
+class CsvDateTime implements Rule
+{
+    const VALID_FORMATS = [
+        'Y/m/d H:i:s',
+        'Y/n/j G:i:s',
+        'Y/m/d H:i',
+        'Y/n/j G:i',
+    ];
+
+    /**
+     * Create a new rule instance.
+     *
+     * @return void
+     */
+    public function __construct()
+    {
+        //
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        // この辺の実装の元ネタは、LaravelのValidatesAttributes#validateDateFormat()
+
+        if (!is_string($value)) {
+            return false;
+        }
+
+        foreach (self::VALID_FORMATS as $format) {
+            $date = \DateTime::createFromFormat('!' . $format, $value);
+
+            if ($date && $date->format($format) === $value) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message()
+    {
+        return ':attribute の形式は "年/月/日 時:分" にしてください。';
+    }
+}
diff --git a/tests/Unit/Io/CheckinCsvImporterTest.php b/tests/Unit/Io/CheckinCsvImporterTest.php
index a85935d..3a81ded 100644
--- a/tests/Unit/Io/CheckinCsvImporterTest.php
+++ b/tests/Unit/Io/CheckinCsvImporterTest.php
@@ -4,34 +4,90 @@ namespace Tests\Unit\Io;
 
 use App\Exceptions\CsvImportException;
 use App\Io\CheckinCsvImporter;
+use App\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Carbon;
 use Tests\TestCase;
 
 class CheckinCsvImporterTest extends TestCase
 {
+    use RefreshDatabase;
+
     public function testIncompatibleCharsetEUCJP()
     {
+        $user = factory(User::class)->create();
         $this->expectException(CsvImportException::class);
         $this->expectExceptionMessage('文字コード判定に失敗しました。UTF-8 (BOM無し) または Shift_JIS をお使いください。');
 
-        $importer = new CheckinCsvImporter(__DIR__ . '/../../fixture/Csv/incompatible-charset.eucjp.csv');
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/incompatible-charset.eucjp.csv');
         $importer->execute();
     }
 
     public function testMissingTimeUTF8()
     {
+        $user = factory(User::class)->create();
         $this->expectException(CsvImportException::class);
         $this->expectExceptionMessage('日時列は必須です。');
 
-        $importer = new CheckinCsvImporter(__DIR__ . '/../../fixture/Csv/missing-time.utf8.csv');
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/missing-time.utf8.csv');
         $importer->execute();
     }
 
     public function testMissingTimeSJIS()
     {
+        $user = factory(User::class)->create();
         $this->expectException(CsvImportException::class);
         $this->expectExceptionMessage('日時列は必須です。');
 
-        $importer = new CheckinCsvImporter(__DIR__ . '/../../fixture/Csv/missing-time.sjis.csv');
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/missing-time.sjis.csv');
         $importer->execute();
     }
+
+    public function testDateNoSecondUTF8()
+    {
+        $user = factory(User::class)->create();
+
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/date-nosecond.utf8.csv');
+        $importer->execute();
+        $ejaculation = $user->ejaculations()->first();
+
+        $this->assertSame(1, $user->ejaculations()->count());
+        $this->assertEquals(Carbon::create(2020, 1, 23, 6, 1, 0), $ejaculation->ejaculated_date);
+    }
+
+    public function testDateNoZeroNoSecondUTF8()
+    {
+        $user = factory(User::class)->create();
+
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/date-nozero-nosecond.utf8.csv');
+        $importer->execute();
+        $ejaculation = $user->ejaculations()->first();
+
+        $this->assertSame(1, $user->ejaculations()->count());
+        $this->assertEquals(Carbon::create(2020, 1, 23, 6, 1, 0), $ejaculation->ejaculated_date);
+    }
+
+    public function testDateUTF8()
+    {
+        $user = factory(User::class)->create();
+
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/date.utf8.csv');
+        $importer->execute();
+        $ejaculation = $user->ejaculations()->first();
+
+        $this->assertSame(1, $user->ejaculations()->count());
+        $this->assertEquals(Carbon::create(2020, 1, 23, 6, 1, 0), $ejaculation->ejaculated_date);
+    }
+
+    public function testDateNoZeroUTF8()
+    {
+        $user = factory(User::class)->create();
+
+        $importer = new CheckinCsvImporter($user, __DIR__ . '/../../fixture/Csv/date-nozero.utf8.csv');
+        $importer->execute();
+        $ejaculation = $user->ejaculations()->first();
+
+        $this->assertSame(1, $user->ejaculations()->count());
+        $this->assertEquals(Carbon::create(2020, 1, 23, 6, 1, 0), $ejaculation->ejaculated_date);
+    }
 }
diff --git a/tests/fixture/Csv/date-nosecond.utf8.csv b/tests/fixture/Csv/date-nosecond.utf8.csv
new file mode 100644
index 0000000..a100b02
--- /dev/null
+++ b/tests/fixture/Csv/date-nosecond.utf8.csv
@@ -0,0 +1,2 @@
+日時
+2020/01/23 06:01
diff --git a/tests/fixture/Csv/date-nozero-nosecond.utf8.csv b/tests/fixture/Csv/date-nozero-nosecond.utf8.csv
new file mode 100644
index 0000000..60cb295
--- /dev/null
+++ b/tests/fixture/Csv/date-nozero-nosecond.utf8.csv
@@ -0,0 +1,2 @@
+日時
+2020/1/23 6:01
diff --git a/tests/fixture/Csv/date-nozero.utf8.csv b/tests/fixture/Csv/date-nozero.utf8.csv
new file mode 100644
index 0000000..e0b3ede
--- /dev/null
+++ b/tests/fixture/Csv/date-nozero.utf8.csv
@@ -0,0 +1,2 @@
+日時
+2020/1/23 6:01:02
diff --git a/tests/fixture/Csv/date.utf8.csv b/tests/fixture/Csv/date.utf8.csv
new file mode 100644
index 0000000..24ee353
--- /dev/null
+++ b/tests/fixture/Csv/date.utf8.csv
@@ -0,0 +1,2 @@
+日時
+2020/01/23 06:01:02
diff --git a/tests/fixture/Csv/incompatible-charset.eucjp.csv b/tests/fixture/Csv/incompatible-charset.eucjp.csv
index 866ed4d..62dcc8d 100644
--- a/tests/fixture/Csv/incompatible-charset.eucjp.csv
+++ b/tests/fixture/Csv/incompatible-charset.eucjp.csv
@@ -1,2 +1,2 @@
 ����,����,���������
-2019-01-01 00:01:02,�ƥ��ȥƥ��Ȥ���������,https://example.com/
+2019/1/01 0:01,�ƥ��ȥƥ��Ȥ���������,https://example.com/